This invention relates to a process and apparatus for the spinning of slivers by means of a ring spinning machine which has a plurality of spinning stations. One sliver respectively which is taken out of a can is fed to the drafting units of the spinning stations.
In the case of fast-running high-production spinning machines, it is customary to feed the fiber material to be spun in the form of slivers deposited in cans. This applies to open-end rotor spinning machines, open-end friction spinning machines, wind-around spinning machines and air spinning machines. The feeding in cans is also known for ring spinning machines, whereby a preceding machine, specifically the flyer spinning frame, is to be saved.
It is an object of the invention to provide a process by which the spinning operation of the individual spinning stations is improved and the costs for manufacturing a yarn are reduced.
This object is achieved according to preferred embodiments of the invention in that the slivers have a size of approximately Nm 0.25 to approximately Nm 0.8 and are guided by means of sliver guiding devices on the path from above the cans to the drafting units which are constructed as three-cylinder drafting units.
By means of this process, the advantage is achieved that finer sliver can be fed to the individual spinning stations, in which case these finer slivers can also be fed along a relatively long length. The spinning of finer slivers has the advantage that finer yarns of a good quality can be spun at the individual spinning stations with lower technical and mechanical expenditures.
In the case of ring spinning machines, the feeding of fine slivers permits an elimination of the preceding flyer spinning frame; that is, the direct spinning of slivers produced on a drafting frame is possible by means of the ring spinning machine. Nevertheless, no complicated drafting units are required for the ring spinning machine. On the contrary, the conventional and proven three-cylinder drafting units will be sufficient.
Relatively old proposals are known by means of which it was attempted to feed a sliver, which comes directly from a drafting frame, in cans to the ring spinning machines so that the flyer spinning frame which customarily precedes ring spinning machines may be eliminated. In this case, it is known (German Patent Document DE-PS 817 572) to set up the cans in two rows in an elevated manner between the two machines sides which are equipped with the drafting units. Each of these cans must contain at least four drawing frame slivers. It is also known (German Patent Document DE-PS 882 068) to deposit the cans on carriages which are set up above or below the spinning machine on intermediate floors, a special platform or a trolley. On the basis of such suggestions, practical tests were carried out in the Fifties which failed, however. On the one hand, the sliver had to be guided along relatively long paths which caused unintentional and uncontrolled drafts in the slivers so that the produced yarns did not have a satisfactory quality. Furthermore, drafting units had to be created which permit a very high draft on the one hand, but, on the other hand, nevertheless have only a relatively low delivery speed. This had the result that the draw-in rollers of such drafting units run at very low rotational speeds, that is, at 2 min.sup.-1 (revolutions per minute) or less. Such rotational speeds can hardly be controlled in the case of drafting units for ring spinning machines which have a considerable length. The draw-in rollers therefore moved jerkily and, because of torsional effects, also at different speeds in the area of the machine end so that additional wrong drafts were caused. These tests were therefore given up in the case of ring spinning machines. Even today, a flyer spinning frame still precedes the ring spinning machine and produces roving bobbins, the roving of which is so fine that it can be processed by three-cylinder drafting units without any difficulty. In this case, it is known to provide the roving withdrawn from the roving bobbins with a false twist before it enters into the drafting units. In one case (European Patent Document EO-0 041 484 B1), the roving is guided over a stationary false-twisting element. In the case of another solution (European Patent Document EP-0 168 357 B1), a special construction of a drafting unit is provided which rotates about the yarn axis. In addition, a suggestion has become known (German Patent Document DE 29 34 830 A1) that, when the slivers produced on a drafting frame are deposited in cans, these slivers are provided with a protective twist by false twisting. However, this arrangement has not been accepted in practice because it was probably overlooked that the false twist opens up downstream of the twist generating devices so that in fact the sliver is not provided with any protective twist.
In the case of wind-around spinning machines, such as the Sussen-Parafil, or in the case of air spinning machines, such as the Sussen-Plyfil, it is known to provide slivers in cans. In these cases, the slivers have relatively coarse sizes so that they withstand the transport from the cans to the drafting unit without any wrong drafts. The drafting units must have a very high draft so that here also the expensive five-cylinder drafting units are provided. The functioning of these expensive drafting units is possible because the spinning in this case takes place at high delivery speeds so that the draw-in rollers rotate at sufficient rotational speeds. By using finer slivers, it becomes possible in the case of these machines to do without the expensive five-cylinder drafting units and to replace them by three-cylinder drafting units which have shown good results in the case of ring spinning machines and which, in addition, are easier to operate.
In a further development of the invention, it is provided that the slivers receive a twist of from 2 to 15 T/m (twists per meter). Since the draw-in speeds of the slivers, also in the case of fast-running spinning machines, such as open-end rotor spinning machines, seldom exceed 1 m/min, the cans must rotate only at relatively low rotational speeds so that they can be driven by simple drives and do not require any excessive technical expenditures and therefore do not cause any excessive costs. The introduced twists, in addition, must not maintain an exact value that remains constant and must also not be distributed absolutely uniformly since the twist is largely or completely opened up again by a drafting or separating of the fibers.
In a further development of the invention, devices for rotating the cans around their axes are provided in the case of spinning machines with several spinning stations for the spinning of yarns from slivers which are withdrawn from cans by devices which are part of the spinning stations. As a result, the slivers are provided with a true twist during the withdrawal so that fine slivers can be processed without the danger of wrong drafts and in this case can also be fed to the individual spinning stations along relatively long paths.
In a further development of the invention, it is provided that the devices for the rotating and the devices for the receiving of the cans, which can be set up in several rows extending in the longitudinal direction of the machine, are arranged above the pertaining spinning machine. This ensures that the space requirement is not increased in comparison to conventional machines with respect to the required area which is particularly significant in the case of ring spinning machines in which the individual spinning stations are arranged on both sides of the machine at a relatively narrow spacing.
In a further development of the invention, it is provided that the devices for the rotating of the cans are assigned to the bottoms of the cans. As a result, it is possible to simply deposit the cans on the devices for the rotating so that the feeding of full cans and the moving-away of empty cans presents no problems. In addition, such devices for the rotating, which are assigned to the bottoms of the cans, require no new can shapes.
In a further development of the invention, it is provided that the devices for the rotating of the cans are arranged in a line-up platform for the cans on which the cans can be deposited in at least two rows extending in the longitudinal direction of the machine. This line-up platform may, for example, in the case of open-end spinning machines, be arranged essentially in front of and under the spinning stations. In the case of one-sided machines, such as the Sussen-Parafil wind-around spinning machine or the Sussen-Plyfil air spinning machine, such a line-up platform may be arranged behind the spinning units, that is, on the side facing away from the operating side.
In the case of ring spinning machines or machines with a similarly narrow spindle gauge, it is expediently provided in another development of the invention that the line-up platform is constructed as an accessible platform. This platform will expediently exhibit a height which is sufficient for leaving an operating aisle for operators and for movable servicing apparatuses.
In a further development of the invention, it is provided that the devices for the rotating comprise rotatably disposed plates which are assigned to one can respectively and which are connected to a rotary drive.
In another embodiment of the invention, an endless driving element is provided as the device for the rotating which extends in parallel to the longitudinal direction of the machine and on which several cans are deposited which are arranged in a row. In this case, it is expedient for devices for fixing the cans in their position to be assigned to the cans. Such driving elements, which may be belts, bands or coated cords, can be implemented very easily.
In a further development of the invention, it is provided that a deflecting device for the slivers is arranged above the cans. This deflecting device provides that, in a known manner, the slivers are withdrawn from the cans essentially upwards. In addition, this deflecting device is also used as a twist stopping device so that the twist introduced by the rotating of the cans is introduced into the slivers in a defined area. In an expedient further development, it is provided that the deflecting device comprises a withdrawal roller pair with at least one drivable withdrawal roller.
In a further development of the invention, it is provided that sliver guiding devices follow the deflecting device which each lead to one spinning station. These sliver guiding devices provide that the slivers move on a defined path. In this case, it is advantageous for guiding tubes to be provided as the sliver guiding devices in a further development. The slivers can relatively easily be sucked or blown into these guiding tubes so that the initial application of the cans to the spinning stations can be carried out relatively easily.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.